CA1061986A - Method and apparatus for continuously casting a slab - Google Patents
Method and apparatus for continuously casting a slabInfo
- Publication number
- CA1061986A CA1061986A CA256,677A CA256677A CA1061986A CA 1061986 A CA1061986 A CA 1061986A CA 256677 A CA256677 A CA 256677A CA 1061986 A CA1061986 A CA 1061986A
- Authority
- CA
- Canada
- Prior art keywords
- wide side
- side walls
- walls
- mold
- strand
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000005266 casting Methods 0.000 title claims description 22
- 238000000034 method Methods 0.000 title claims description 8
- 238000001816 cooling Methods 0.000 claims abstract description 27
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 8
- 239000010959 steel Substances 0.000 claims abstract description 8
- 239000002826 coolant Substances 0.000 claims description 15
- 239000012530 fluid Substances 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 7
- 238000005304 joining Methods 0.000 claims description 2
- 238000009749 continuous casting Methods 0.000 abstract description 6
- 239000000498 cooling water Substances 0.000 description 9
- 238000005452 bending Methods 0.000 description 6
- 230000008719 thickening Effects 0.000 description 5
- 230000035882 stress Effects 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- 238000007711 solidification Methods 0.000 description 3
- 230000008023 solidification Effects 0.000 description 3
- 239000007921 spray Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- NLZUEZXRPGMBCV-UHFFFAOYSA-N Butylhydroxytoluene Chemical compound CC1=CC(C(C)(C)C)=C(O)C(C(C)(C)C)=C1 NLZUEZXRPGMBCV-UHFFFAOYSA-N 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/124—Accessories for subsequent treating or working cast stock in situ for cooling
- B22D11/1243—Accessories for subsequent treating or working cast stock in situ for cooling by using cooling grids or cooling plates
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
In the continuous casting of very wide steel slabs, the use of the conventional transverse rollers to support the wide side walls of the slab to prevent bulging or deflection thereof due to the ferrostatic pressure applied thereto by the molten core or due to other stresses is avoided by applying intensive cooling to the surfaces of the narrow end walls of the slab and to the surfaces of the immediately adjoining wide side walls to increase the wall thickness of said end walls and of the immediately adjoining wide side walls more rapidly than the thickness of the portions of the wide side walls extending laterally therefrom is increased whereby the thickened end walls and immediately adjoining thickened portions of the wide side walls act as the ends of constrained beams to support and resist deflection of the remaining portions of the wide side walls.
In the continuous casting of very wide steel slabs, the use of the conventional transverse rollers to support the wide side walls of the slab to prevent bulging or deflection thereof due to the ferrostatic pressure applied thereto by the molten core or due to other stresses is avoided by applying intensive cooling to the surfaces of the narrow end walls of the slab and to the surfaces of the immediately adjoining wide side walls to increase the wall thickness of said end walls and of the immediately adjoining wide side walls more rapidly than the thickness of the portions of the wide side walls extending laterally therefrom is increased whereby the thickened end walls and immediately adjoining thickened portions of the wide side walls act as the ends of constrained beams to support and resist deflection of the remaining portions of the wide side walls.
Description
106~ 36 This invention relates to the continuous casting of a steel strand in the form of a rectangular slab having opposed wide side walls and opposed narrow end walls joining said wide side walls.
In the steel industry, in the use of continuous cast-ing, the recent trend of thinking has been in the direction of cas~ing wider and wider slabs, which, after solidification, may be slit longitudinally to provide narrower slabs or shapes for subsequent processing such as rolling, for example. Up to the present time, because of the complicated equipment required, it has not appeared practical to cast slabs having a width in excess of 80", but it has been recognized that important ad-vantages could be realized if it became possible to cast even wider slabs having a width of 100" or more. ~or example, a slab having a width of 120" could be slit longitudinally to pro-vide slabs of various widths totalling 120". This would be far more economical than casting individual slabs of such widths, and would avoid the need for frequent mold changes to cast in-dividual slabs of the desired widths and would thereby increase the capacity of the machine. It w~uld also avoid the need to use multiple strand continuous casting machines which are costly and difficult to operate.
However, it has also been recognized that serious mechanical and economic problems are involved in the construction ~5 and operation of continuous casting machines capable of casting slabs even of a width of 80" and these problems are magnified in the case of ~achines capable of casting slabs wider than this. One of the most serious problems has to do with the so-called "roller aprons" now conventionally used in the secondary cooling ~one of continuous casting machines to support the walls of the casting below the mold to prevent bulging or deflection of the walls and possible rupture and spills of molten metal due to the ferrostatic pressure applied to the walls by the ~06~98~i molten metal core. The dlsclosures of Patents Nos. 3,752,2l0, 3,763~923 and 3,8311661 illustrate and describe some of the complexities and problems of such rollers aprons or roll racks as they are sometimes referred to.
This problem is particularly serious in the case of slab casting~ and increases as the width of the slab is in-creased. That is, as the width of the slab is increased, the diameter of the rollers must be increased in order to provide the necessary strength and rigidity to resist bending. This requires the use of larger and stronger hydraulic supports, load cells and bearings for the rollers, all of which vastly increases the cost of the machines and the maintenance thereof. In add-ition9 even these rolls are subject to breakage due to the heat and pressure to which they are subjected, and the wider the slab the greater the press~ures applied thereto. More importaNtly, the use of the larger diameter rollers increases the difficulty of applying cooling water ~o the strand as it moves through the secondary cooling zone. That is, the cooling water is applied to the surfaces of the wide sides of the sla~ through the spaces between adjacent successive rollers. Therefore, as the diameter of the rollers is increased, the distance between the axes of rotation of successive rollers must be increased, with the result that the distance between successive applications o~ cooling water is also increased. Even in existing machines, such rollers sometimes occupy up to 80% of the surfaces of the wide sides of the slab.
In my prior patents Nos. 3,766,962 and 3,765,472, I have dealt with this problem by casting a slab in which the oppositely disposed wide side walls thereof are concavely arched in order to resist outward bulging or deflection caused ~y the ferrostatic pressure applied thereto by the molten metal core. In No. 3,766,962, the concavely arched walls are maintained within the secondary cooling zone by the compressive stresses ~6~L9~36 -applied to the ~arrow end walls of the slab in a direction transverse of the slab. In No. 3,765,472, the concavely ar~hed walls are maintained within the secondary cooling zone by the application of intensive cooling to the concavely arched sur-faces of the wide side walls to establish thermal stresses within the side walls which resist bulging or deflection caused by ferrostatic pressure.
In both cases, the described methods permit the elim-ination of the rollers, thus making possible the continuous, tn-in~errupted application of cooling water to the wide side sur-faces of the strand longitudinally of the strand which promotes more rapid cooling and solidification and thereby makes lt possible to greatly reduce the length of the machine and its cost.
It i5 an obiect of the present invention ~o provide another method of preventing bulging or deflection of the wide side walls of continuously cast slabs within the secondary cooling zone without the use of supporting rollers as in the conventional roller aprons.
According to the present invention, I propose to subject the surfaces of the narrow end walls and the surfaces of the wide side walls immediately adjoining them to very intensive cooling below the mold by applying coolant fluid directly onto said surfaces to rapidly build up solidified metal in said narrow end walls and in portions of said side walls immedlately adjoining said end walls, while simultaneous-ly subjecting the other surfaces of said wide side walls extend-ing laterally therefro~ to less intensive cooling by applying coolant fluid directly onto said sur~aces, the coolant applied 3~ to said narrow end surfaces and to said immediately adjoining wide side surfaces being applied at sufficiently high intensity to increase the wall thickness of said end walls and of the immediately adjoining wide side walls more rapidly than the thickness of those portians of said wide side walls extending laterally therefrom is increased by the coolant applied there-to, whereby the thickened end walls and immediately adjoining thickened portions of said wide side walls act as the ends of constrained beams to support and resist deflection of the re-maining portions of the wide side walls due to the ferrostatic pressure of said molten core or other causes. The coolant fluid is continuously applied to said narrow end and wide side surfaces extending longitudinally of said strand from the level where the strand emerges from the mold to the level where the walls of said shell become self-sustaining. The method :is particularly advantageous when used in connection with slabs as initially formed in the mold with concavely arched wide side walls, a~though it may also be used to advantage in con-nection with slabs initially formed with flat wide side walls.
According to the present invention, it is also pro-posed to provide mechanical support for the wide side walls immediately below the mold by the provision of cooling plates or grids extending downwardly from the bottom of the mold along ~0 the wide sides thereof and having surfaces conforming to the contours of the slab surfaces to which they are opposed. The said plates or grids are provided with passages or apertures through which cooling water may be applied to the opposed sur-: faces of the slab, and the areas of the plates or grids are preferably restricted to opposed those areas of the wide sidewalls of the slab within which bending stresses and the maxi-mum deflection are most li~ely to occur. It is recognized that due to the action of the constrained beams as above described, the regions where the wide side walls are subjected to maximum bending stresses resulting from ferrostatic pressures applied thereto are those immediately adjoining the thickaned portions created by application of intensive cooling, and that the maximum deflection resulting from any bending which may occur will be at the center of the walls immediately below the mold.
1~)6198~ 1 It is also recognized that the danger of such bending and deflection recedes as the strand moves through the ~econdary cooling zone an~ the solidification o the walls proceeds and the width o ~he liquid crater narrows. Thereore, the plates or grids are preferably triangular in shap~- and are arranged in pairs with one pair opposed to each wide side wall. Th0 bases of the triangles are located adjacent to the bottom o~ the mold with the apexes of th~ triangles pointing downwardly and extending at least to the level where the wall thiclcness of the solidified shell becomes ~elf-sustaining. The outsiae edges of the triangles are preferably tapered away from the edges of the slab walls which are already solidified as they no longer need support. The inside edges of the triangles preferably diverge away from the longitudinal center of the slab as the so~idified ~hell thickens and it becomes more than strong enough to support ~he ferrosta~ic pressure.
It will be understood that the prLmary purpose of said plates or grids is precautionary and to provide safety against unexpected or ~xcessive deflect~on of the side walls, particularly i~ the region close to the bottom of the mold, due to inadequate cooling of the end walls or due to changes ~n conditions such as changes in temperature ~f the metal flowing into the mold, changes in t2mperature or quantity of the cooling water, changes in ra~e of withdrawal and the like.
In accordance with one broad aspect, the invention relates to the ~ethod o~ continuously casting a steel ~tr~nd in the form of a rectangular sl~b having opposed wide side wzllls and opposed narr~7 end walls ~oining said w~de side walls ~hich comprises pouring molten steel into the upper end of a chilled mold having a mold pa~ge of sub~tan~ial~y rectangular cross sec~ion, continuously withdr~wing from said mold a partially solidified stra~d comprising rel~tively thin solidified side ~nd end walls ~ ~ - 6 -1o6l9~6 forming an outer shell surrounding an inner molten core, subjecting the surfaces o said narrow end walls and the surfaces of the wide side walls immediate:Ly adjoining them to very intensive cool.ing below said mold by applying coolant fluid directly o~to said surfaces to rapidly build up solidified metal in said narrow end walls and in portions o~ said side walls immediately adjoining said en~ walls, simultaneously subjecting the other surfaces of said wide side walls extending laterally therefrom to less intensive cooling by applying coolant fluid directly onto said surfaces so that there is a differential in the intensity of the cooling applied to the respective surfaces, the coolant applied to said narrow end Qurfaces and to said immediately adjoining wide side surfaces being applied at sufficiently high intensity to increase the wall thickness of said end walls and o$ the immediately adjoining wide side walls more rapidly t~an thickness of those portions of said wide side walls extending laterally therefrom is increased by the coolant applied thereto, whereby the thickenea end walls and immediately adjoining thickened portionR of ~aid wide ~ide walls act ~s the ends of constrained beams to support and resist deflection of remaining portions of the wide side walls caused by the ferro-static pre~sure of said molten core, and continuously applying coolant fluid to said narrow end and wide side surfaces of such differential intensities along continuous areas o~ said surfaces extendlng longitudinally of ~id strand from the level where the strand emerges from the mold to the level where the walls of said shell become self-su~t~ining.
A semi-di~grammatic illustra~ion o~ a preferred embodiment o~ apparatus in ~hi~h the method o the i~vention may 3D be practic~d ~s ~hown in the acc~mpanying drawing, ln which:
Fig. 1 i~ ~ side elev~tion o the apparatus, partly broken away.
~ - 6A
Fig. 2 is an enlarged ~ront elevation of a portion of the apparatus adjacent the bottom of the mold.
Fig. 3 is a section on the line 3-3 of Fig. 2 showing the thickening of the narrow end walls of t:he casting.
r ~ ~ ~ ~ 6B -Fig. ~ is a s~milar section on the line 4-4 of Fig.
In the steel industry, in the use of continuous cast-ing, the recent trend of thinking has been in the direction of cas~ing wider and wider slabs, which, after solidification, may be slit longitudinally to provide narrower slabs or shapes for subsequent processing such as rolling, for example. Up to the present time, because of the complicated equipment required, it has not appeared practical to cast slabs having a width in excess of 80", but it has been recognized that important ad-vantages could be realized if it became possible to cast even wider slabs having a width of 100" or more. ~or example, a slab having a width of 120" could be slit longitudinally to pro-vide slabs of various widths totalling 120". This would be far more economical than casting individual slabs of such widths, and would avoid the need for frequent mold changes to cast in-dividual slabs of the desired widths and would thereby increase the capacity of the machine. It w~uld also avoid the need to use multiple strand continuous casting machines which are costly and difficult to operate.
However, it has also been recognized that serious mechanical and economic problems are involved in the construction ~5 and operation of continuous casting machines capable of casting slabs even of a width of 80" and these problems are magnified in the case of ~achines capable of casting slabs wider than this. One of the most serious problems has to do with the so-called "roller aprons" now conventionally used in the secondary cooling ~one of continuous casting machines to support the walls of the casting below the mold to prevent bulging or deflection of the walls and possible rupture and spills of molten metal due to the ferrostatic pressure applied to the walls by the ~06~98~i molten metal core. The dlsclosures of Patents Nos. 3,752,2l0, 3,763~923 and 3,8311661 illustrate and describe some of the complexities and problems of such rollers aprons or roll racks as they are sometimes referred to.
This problem is particularly serious in the case of slab casting~ and increases as the width of the slab is in-creased. That is, as the width of the slab is increased, the diameter of the rollers must be increased in order to provide the necessary strength and rigidity to resist bending. This requires the use of larger and stronger hydraulic supports, load cells and bearings for the rollers, all of which vastly increases the cost of the machines and the maintenance thereof. In add-ition9 even these rolls are subject to breakage due to the heat and pressure to which they are subjected, and the wider the slab the greater the press~ures applied thereto. More importaNtly, the use of the larger diameter rollers increases the difficulty of applying cooling water ~o the strand as it moves through the secondary cooling zone. That is, the cooling water is applied to the surfaces of the wide sides of the sla~ through the spaces between adjacent successive rollers. Therefore, as the diameter of the rollers is increased, the distance between the axes of rotation of successive rollers must be increased, with the result that the distance between successive applications o~ cooling water is also increased. Even in existing machines, such rollers sometimes occupy up to 80% of the surfaces of the wide sides of the slab.
In my prior patents Nos. 3,766,962 and 3,765,472, I have dealt with this problem by casting a slab in which the oppositely disposed wide side walls thereof are concavely arched in order to resist outward bulging or deflection caused ~y the ferrostatic pressure applied thereto by the molten metal core. In No. 3,766,962, the concavely arched walls are maintained within the secondary cooling zone by the compressive stresses ~6~L9~36 -applied to the ~arrow end walls of the slab in a direction transverse of the slab. In No. 3,765,472, the concavely ar~hed walls are maintained within the secondary cooling zone by the application of intensive cooling to the concavely arched sur-faces of the wide side walls to establish thermal stresses within the side walls which resist bulging or deflection caused by ferrostatic pressure.
In both cases, the described methods permit the elim-ination of the rollers, thus making possible the continuous, tn-in~errupted application of cooling water to the wide side sur-faces of the strand longitudinally of the strand which promotes more rapid cooling and solidification and thereby makes lt possible to greatly reduce the length of the machine and its cost.
It i5 an obiect of the present invention ~o provide another method of preventing bulging or deflection of the wide side walls of continuously cast slabs within the secondary cooling zone without the use of supporting rollers as in the conventional roller aprons.
According to the present invention, I propose to subject the surfaces of the narrow end walls and the surfaces of the wide side walls immediately adjoining them to very intensive cooling below the mold by applying coolant fluid directly onto said surfaces to rapidly build up solidified metal in said narrow end walls and in portions of said side walls immedlately adjoining said end walls, while simultaneous-ly subjecting the other surfaces of said wide side walls extend-ing laterally therefro~ to less intensive cooling by applying coolant fluid directly onto said sur~aces, the coolant applied 3~ to said narrow end surfaces and to said immediately adjoining wide side surfaces being applied at sufficiently high intensity to increase the wall thickness of said end walls and of the immediately adjoining wide side walls more rapidly than the thickness of those portians of said wide side walls extending laterally therefrom is increased by the coolant applied there-to, whereby the thickened end walls and immediately adjoining thickened portions of said wide side walls act as the ends of constrained beams to support and resist deflection of the re-maining portions of the wide side walls due to the ferrostatic pressure of said molten core or other causes. The coolant fluid is continuously applied to said narrow end and wide side surfaces extending longitudinally of said strand from the level where the strand emerges from the mold to the level where the walls of said shell become self-sustaining. The method :is particularly advantageous when used in connection with slabs as initially formed in the mold with concavely arched wide side walls, a~though it may also be used to advantage in con-nection with slabs initially formed with flat wide side walls.
According to the present invention, it is also pro-posed to provide mechanical support for the wide side walls immediately below the mold by the provision of cooling plates or grids extending downwardly from the bottom of the mold along ~0 the wide sides thereof and having surfaces conforming to the contours of the slab surfaces to which they are opposed. The said plates or grids are provided with passages or apertures through which cooling water may be applied to the opposed sur-: faces of the slab, and the areas of the plates or grids are preferably restricted to opposed those areas of the wide sidewalls of the slab within which bending stresses and the maxi-mum deflection are most li~ely to occur. It is recognized that due to the action of the constrained beams as above described, the regions where the wide side walls are subjected to maximum bending stresses resulting from ferrostatic pressures applied thereto are those immediately adjoining the thickaned portions created by application of intensive cooling, and that the maximum deflection resulting from any bending which may occur will be at the center of the walls immediately below the mold.
1~)6198~ 1 It is also recognized that the danger of such bending and deflection recedes as the strand moves through the ~econdary cooling zone an~ the solidification o the walls proceeds and the width o ~he liquid crater narrows. Thereore, the plates or grids are preferably triangular in shap~- and are arranged in pairs with one pair opposed to each wide side wall. Th0 bases of the triangles are located adjacent to the bottom o~ the mold with the apexes of th~ triangles pointing downwardly and extending at least to the level where the wall thiclcness of the solidified shell becomes ~elf-sustaining. The outsiae edges of the triangles are preferably tapered away from the edges of the slab walls which are already solidified as they no longer need support. The inside edges of the triangles preferably diverge away from the longitudinal center of the slab as the so~idified ~hell thickens and it becomes more than strong enough to support ~he ferrosta~ic pressure.
It will be understood that the prLmary purpose of said plates or grids is precautionary and to provide safety against unexpected or ~xcessive deflect~on of the side walls, particularly i~ the region close to the bottom of the mold, due to inadequate cooling of the end walls or due to changes ~n conditions such as changes in temperature ~f the metal flowing into the mold, changes in t2mperature or quantity of the cooling water, changes in ra~e of withdrawal and the like.
In accordance with one broad aspect, the invention relates to the ~ethod o~ continuously casting a steel ~tr~nd in the form of a rectangular sl~b having opposed wide side wzllls and opposed narr~7 end walls ~oining said w~de side walls ~hich comprises pouring molten steel into the upper end of a chilled mold having a mold pa~ge of sub~tan~ial~y rectangular cross sec~ion, continuously withdr~wing from said mold a partially solidified stra~d comprising rel~tively thin solidified side ~nd end walls ~ ~ - 6 -1o6l9~6 forming an outer shell surrounding an inner molten core, subjecting the surfaces o said narrow end walls and the surfaces of the wide side walls immediate:Ly adjoining them to very intensive cool.ing below said mold by applying coolant fluid directly o~to said surfaces to rapidly build up solidified metal in said narrow end walls and in portions o~ said side walls immediately adjoining said en~ walls, simultaneously subjecting the other surfaces of said wide side walls extending laterally therefrom to less intensive cooling by applying coolant fluid directly onto said surfaces so that there is a differential in the intensity of the cooling applied to the respective surfaces, the coolant applied to said narrow end Qurfaces and to said immediately adjoining wide side surfaces being applied at sufficiently high intensity to increase the wall thickness of said end walls and o$ the immediately adjoining wide side walls more rapidly t~an thickness of those portions of said wide side walls extending laterally therefrom is increased by the coolant applied thereto, whereby the thickenea end walls and immediately adjoining thickened portionR of ~aid wide ~ide walls act ~s the ends of constrained beams to support and resist deflection of remaining portions of the wide side walls caused by the ferro-static pre~sure of said molten core, and continuously applying coolant fluid to said narrow end and wide side surfaces of such differential intensities along continuous areas o~ said surfaces extendlng longitudinally of ~id strand from the level where the strand emerges from the mold to the level where the walls of said shell become self-su~t~ining.
A semi-di~grammatic illustra~ion o~ a preferred embodiment o~ apparatus in ~hi~h the method o the i~vention may 3D be practic~d ~s ~hown in the acc~mpanying drawing, ln which:
Fig. 1 i~ ~ side elev~tion o the apparatus, partly broken away.
~ - 6A
Fig. 2 is an enlarged ~ront elevation of a portion of the apparatus adjacent the bottom of the mold.
Fig. 3 is a section on the line 3-3 of Fig. 2 showing the thickening of the narrow end walls of t:he casting.
r ~ ~ ~ ~ 6B -Fig. ~ is a s~milar section on the line 4-4 of Fig.
2 showing the progressive thickening of the narrow end walls.
Referring to the drawings, the appa~at~ts comprises a water cooled mold 1 into which molten steel is poured continu-ously from a tundish 2 of conven~ional construction. The mold 1 is also of conventional construction except that a major portion of ~he surfaces of each of the wide side walls of the mold passage is slightly convex in transverse cross sectional contour in order that the major poxtion of ~e surfaces oE each of the wide side walls 3 of the casting will be slightly con-cave in transverse cross section as shown in Fig. 3. Thereby ~ each d the wide side walls of the casting is in the form of an - arch which tends to resis~ deflection due to ferrostatic pressure applied by the molten core 4. Preferably, the surfaces of the narrow end walls 5 of the casting are flat as shown in Fig. 3 and adjoining relatively narrow areas 6 of the surfaces of the wide side walls are flat. The said flat surfaces are adapted to be engaged by the short rollers 7 which support and guide the casting durlng its progress through the secondary cooling zone.
Preferably also, the mold passage through the mold within which the walls of the casting are formed initially is curved in accordance with the discloaure of Schneckenburger U. S. Patent 2,947,075, so that the partially solidified strand 8 which emerges from the mold is curved longitudinally as shown in Fig. 1 for reasons described in said patent. It will be understood that the movement of the strand through the secondary cooling zone is controlled by conventional withdrawal rolls 9.
In ord~r to apply very intensive cooling to the sur-faces of the narrow end walls of the casting, and to the sur-faces of the wide side walls immediately adjoin,~ng said end walls a series of clusters of closely spaced nozzles 11 are ~a 6~ 6 provided through which sprays o cooling water are discharged at high pressure. The said clusters extend from immediately below the mold at least ~o a point where the walls of the strand are sufficiently solidified to be se:Lf-supporting.
The application o very intensive cooling to the surfaces of the narrow end walls of the casting and to the surfaces of the wide side walls immediately adjoining said end walls results in a rapid thickening of the end walls as indicated at 12 o Fig.
Referring to the drawings, the appa~at~ts comprises a water cooled mold 1 into which molten steel is poured continu-ously from a tundish 2 of conven~ional construction. The mold 1 is also of conventional construction except that a major portion of ~he surfaces of each of the wide side walls of the mold passage is slightly convex in transverse cross sectional contour in order that the major poxtion of ~e surfaces oE each of the wide side walls 3 of the casting will be slightly con-cave in transverse cross section as shown in Fig. 3. Thereby ~ each d the wide side walls of the casting is in the form of an - arch which tends to resis~ deflection due to ferrostatic pressure applied by the molten core 4. Preferably, the surfaces of the narrow end walls 5 of the casting are flat as shown in Fig. 3 and adjoining relatively narrow areas 6 of the surfaces of the wide side walls are flat. The said flat surfaces are adapted to be engaged by the short rollers 7 which support and guide the casting durlng its progress through the secondary cooling zone.
Preferably also, the mold passage through the mold within which the walls of the casting are formed initially is curved in accordance with the discloaure of Schneckenburger U. S. Patent 2,947,075, so that the partially solidified strand 8 which emerges from the mold is curved longitudinally as shown in Fig. 1 for reasons described in said patent. It will be understood that the movement of the strand through the secondary cooling zone is controlled by conventional withdrawal rolls 9.
In ord~r to apply very intensive cooling to the sur-faces of the narrow end walls of the casting, and to the sur-faces of the wide side walls immediately adjoin,~ng said end walls a series of clusters of closely spaced nozzles 11 are ~a 6~ 6 provided through which sprays o cooling water are discharged at high pressure. The said clusters extend from immediately below the mold at least ~o a point where the walls of the strand are sufficiently solidified to be se:Lf-supporting.
The application o very intensive cooling to the surfaces of the narrow end walls of the casting and to the surfaces of the wide side walls immediately adjoining said end walls results in a rapid thickening of the end walls as indicated at 12 o Fig.
3. The progressively grea~er thickening of said walls as the strand moves through the secondar~ cooling zone is indicated in Fig. 4. This thickening enables the end walls and immedi-ately adjoining portions of the side walls to act as the ends of constrained beams to support and resist deflection of the remaining portions of the wide side walls caused by the ferro-static pressure of said molten core.
This resistance to deflection is aided by the simul-; taneous application of cooling to the remaining sur~aces of the wide side walls, ~ut such cooling is applied less intensively than that applied to ~he other surfaces as previously des-cribed. For this purpose, spray nozzles 13 are provided through which cooling water may be directed t~ward the said surfaces of the wide side walls.
Mechanical support for limited areas of the wide side walls of the strand are provided by supporting plates or grids extending downwardly from the mold. In the preferxed embodiment illustrated, such mechanical suppor~ is provided by plates 1~.
The said plates are preferably triangular shaped and have sur-faces conforming ~o the contours of the surfaces of th~ wide side walls to which they are opposed. That is, in transverse cross section, the plates are curved to conform to the curved arched contours of the wide side walls, and in longitudinal cross section, they are curved to conform to the longitudinal curvature of the strand. A pair of such plates is provided for ~ L~61~38~
each wide side wall, and each plate is provided with a multi-plicity o~ apertures 15 through which cooling water may pass into the space between the surfaces of the plates and the sur-~aces of the casting to cool the casting and to provide lubric-ation between the surfaces. ~lternativel~, the plates may behollow and provided with apertured walls opposed to the surfaces of the casting through which water may flow. Alternatively, also the mechanical supports may be in the form of grids com-prising a plurali~y o longitudinally extending bars of varying lengths each forming a triangular shaped assembly similar to the shape of the triangular plates 14.
The outside edges of the plates or grids are preferably tapered inwardly away from the edges of the wide side walls, and the inside edges of the plates or grids diverge from the center of the slab. Thus, the supporting members are designed to provide maximum support for the wide side walls of the casting along the regions where the bending stresses are at a maximum and where the maximum deflection is li~ely to occur as herein-before explained. By so designing the supporting members, the friction between the strand and the supporting members is mini~
mized, while at ths same time the exposure of the surface of the casting to cooling is increased.
This resistance to deflection is aided by the simul-; taneous application of cooling to the remaining sur~aces of the wide side walls, ~ut such cooling is applied less intensively than that applied to ~he other surfaces as previously des-cribed. For this purpose, spray nozzles 13 are provided through which cooling water may be directed t~ward the said surfaces of the wide side walls.
Mechanical support for limited areas of the wide side walls of the strand are provided by supporting plates or grids extending downwardly from the mold. In the preferxed embodiment illustrated, such mechanical suppor~ is provided by plates 1~.
The said plates are preferably triangular shaped and have sur-faces conforming ~o the contours of the surfaces of th~ wide side walls to which they are opposed. That is, in transverse cross section, the plates are curved to conform to the curved arched contours of the wide side walls, and in longitudinal cross section, they are curved to conform to the longitudinal curvature of the strand. A pair of such plates is provided for ~ L~61~38~
each wide side wall, and each plate is provided with a multi-plicity o~ apertures 15 through which cooling water may pass into the space between the surfaces of the plates and the sur-~aces of the casting to cool the casting and to provide lubric-ation between the surfaces. ~lternativel~, the plates may behollow and provided with apertured walls opposed to the surfaces of the casting through which water may flow. Alternatively, also the mechanical supports may be in the form of grids com-prising a plurali~y o longitudinally extending bars of varying lengths each forming a triangular shaped assembly similar to the shape of the triangular plates 14.
The outside edges of the plates or grids are preferably tapered inwardly away from the edges of the wide side walls, and the inside edges of the plates or grids diverge from the center of the slab. Thus, the supporting members are designed to provide maximum support for the wide side walls of the casting along the regions where the bending stresses are at a maximum and where the maximum deflection is li~ely to occur as herein-before explained. By so designing the supporting members, the friction between the strand and the supporting members is mini~
mized, while at ths same time the exposure of the surface of the casting to cooling is increased.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. The method of continuously casting a steel strand in the form of a rectangular slab having opposed wide side walls and opposed narrow end walls joining said wide side walls which comprises pouring molten steel into the upper end of a chilled mold having a mold passage of substantially rectangular cross section, continuously withdrawing from said mold a partially solidified strand comprising relatively thin solidified side and end walls forming an outer shell surrounding an inner molten core, subjecting the surfaces of said narrow end walls and the surfaces of the wide side walls immediately adjoining them to very intensive cooling below said mold by applying coolant fluid directly onto said surfaces to rapidly build up solidified metal in said narrow end walls and in portions of said side walls immediately adjoining said end walls, simultaneously subjecting the other surfaces of said wide side walls extending laterally therefrom to less intensive cooling by applying a coolant fluid directly onto said surfaces so that there is a differential in the intensity of the cooling applied to the respective surfaces, the coolant applied to said narrow end surfaces and to said immediately adjoining wide side surfaces being applied at sufficiently high intensity to increase the wall thickness of said end walls and of the immediately adjoining wide side walls more rapidly than the thickness of those portions of said wide side walls extending laterally therefrom is increased by the coolant applied thereto, whereby the thickened end walls and immediately adjoining thickened portions of said wide side walls act as the ends of constrained beams to support and resist deflection of remaining portions of the wide side walls caused by the ferrostatic pressure of said molten core, and continuously applying coolant fluid to said narrow end and wide side surfaces of such defferential intensities along continuous areas of said surfaces extending longitudinally of said strand from the level where the strand emerges from the mold to the level where the walls of said shell become self-sustaining.
2. The method of claim 1 in which said wide side walls are cast in the form of curved arches extending transversely of the strand.
3. The method of claim 1 which includes applying mechanical support to each of the wide side walls of said strand below the mold along pairs of triangular shaped areas in which the outside borders of each area are spaced from the outside edges of said wide side walls and converge inwardly toward the longitudinal center of the strand and the inside borders of each area diverge outwardly from the center, said mechanical support being applied from the level where the strand emerges from the mold to the level where the walls of said shell become self self-sustaining.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/619,464 US4036281A (en) | 1975-10-03 | 1975-10-03 | Method for continuously casting a slab |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1061986A true CA1061986A (en) | 1979-09-11 |
Family
ID=24482046
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA256,677A Expired CA1061986A (en) | 1975-10-03 | 1976-07-09 | Method and apparatus for continuously casting a slab |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4036281A (en) |
| JP (1) | JPS5244727A (en) |
| BR (1) | BR7605553A (en) |
| CA (1) | CA1061986A (en) |
| DE (1) | DE2616487A1 (en) |
| FR (1) | FR2326255A1 (en) |
| GB (1) | GB1535400A (en) |
| IT (1) | IT1073403B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5941829B2 (en) * | 1980-07-03 | 1984-10-09 | 新日本製鐵株式会社 | Continuous steel casting method |
| JPS57127505A (en) * | 1981-01-22 | 1982-08-07 | Nippon Steel Corp | Direct rolling manufacturing device for steel |
| JPS59162354A (en) * | 1983-03-08 | 1984-09-13 | Nissan Motor Co Ltd | Fuel filter |
| JPS59199324A (en) * | 1983-04-25 | 1984-11-12 | Nissan Motor Co Ltd | Filter device of fuel tank |
| US7451804B2 (en) * | 2006-11-22 | 2008-11-18 | Peterson Oren V | Method and apparatus for horizontal continuous metal casting in a sealed table caster |
| CN102303104A (en) * | 2011-09-30 | 2012-01-04 | 中冶南方工程技术有限公司 | Method for controlling narrow side bulging in continuous casting of ultra-thick plate blanks |
| CN104399923B (en) * | 2014-11-18 | 2016-07-06 | 钢铁研究总院 | A kind of method producing special heavy plate continuous casting billet |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2770021A (en) * | 1952-10-23 | 1956-11-13 | Babcock & Wilcox Co | Method of and apparatus for continuous casting |
| US2789328A (en) * | 1954-11-19 | 1957-04-23 | Kaiser Aluminium Chem Corp | Apparatus for casting of metals |
| CH438594A (en) * | 1966-05-31 | 1967-06-30 | Concast Ag | Method and device for cooling continuously cast material |
| US3499456A (en) * | 1967-06-05 | 1970-03-10 | Marotta Valve Corp | Fluid flow control system |
| DE2053947C3 (en) * | 1970-11-03 | 1975-01-16 | Demag Ag, 4100 Duisburg | Method and device for generating coolant jets for cooling metal cast strands |
| US3709648A (en) * | 1970-11-27 | 1973-01-09 | Bertrams Ag Hch | Apparatus for the production of blocks from sodium hydroxide solution |
| US3765472A (en) * | 1971-02-11 | 1973-10-16 | I Rossi | Improvements in supporting slabs during continuous casting |
| AT325232B (en) * | 1973-03-15 | 1975-10-10 | Schoeffmann Rudolf Dipl Ing | PROCESS FOR BENDING AND LEVELING THE CAST RAND IN CONTINUOUS CASTING PLANTS |
| CH559586A5 (en) * | 1973-06-04 | 1975-03-14 | Concast Ag | |
| DE2401263A1 (en) * | 1974-01-11 | 1975-07-24 | Sack Gmbh Maschf | Cooling system for sec cooling zone in continuous casting - edges of slab shielded to retard their cooling rate |
-
1975
- 1975-10-03 US US05/619,464 patent/US4036281A/en not_active Expired - Lifetime
-
1976
- 1976-04-14 DE DE19762616487 patent/DE2616487A1/en active Pending
- 1976-06-08 JP JP51066153A patent/JPS5244727A/en active Pending
- 1976-06-15 GB GB24788/76A patent/GB1535400A/en not_active Expired
- 1976-07-09 CA CA256,677A patent/CA1061986A/en not_active Expired
- 1976-07-30 IT IT50701/76A patent/IT1073403B/en active
- 1976-08-19 FR FR7625238A patent/FR2326255A1/en active Pending
- 1976-08-20 BR BR7605553A patent/BR7605553A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE2616487A1 (en) | 1977-04-14 |
| US4036281A (en) | 1977-07-19 |
| IT1073403B (en) | 1985-04-17 |
| BR7605553A (en) | 1977-08-09 |
| FR2326255A1 (en) | 1977-04-29 |
| JPS5244727A (en) | 1977-04-08 |
| GB1535400A (en) | 1978-12-13 |
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